1. Structured

The data that can be stored and processed in a fixed format. It is easy to process as it has a fixed schema.

1. Semi-Structured

Semi-Structured Data is a type of data which does not have a formal structure of a data model, i.e. a table definition, but nevertheless it has some organizational properties like tags and other markers to separate semantic elements that makes it easier to analyze. XML files are examples of semi-structured data.

1. Unstructured

The data which has unknown form and cannot be stored and analyzed unless it is transformed into a structured format. Text Files and multimedia contents like images, audios, videos are example of unstructured data. The unstructured data is growing quicker than others, experts say that 80 percent of the data in an organization are unstructured.

Source: <https://www.edureka.co/blog/big-data-tutorial>